Reduced estrogen signaling contributes to bone loss and cardiac dysfunction in interleukin-10 knockout mice

Characterization of the interleukin (IL)-10 knockout (KO) mouse with chronic gut inflammation, cardiovascular dysfunction, and bone loss suggests a critical role for this cytokine in interorgan communication within the gut, bone, and cardiovascular axis. We sought to understand the role of IL-10 in the cross-talk between these systems. Six-week-old IL-10 KO mice and their wild type (WT) counterparts were maintained on a standard rodent diet for 3 or 6 months. Gene expression of proinflammatory markers and Fgf23, serum 17β-estradiol (E2), and cardiac protein expression were assessed. Ileal Il17a and Tnf mRNA increased while Il6 mRNA increased in the bone and heart by at least 2-fold in IL-10 KO mice. Bone Dmp1 and Phex mRNA were repressed at 6 months in IL-10 KO mice, resulting in increased Fgf23 mRNA (~4-fold) that contributed to increased fibrosis. In the IL-10 KO mice, gut bacterial β-glucuronidase activity and ovarian Cyp19a1 mRNA were lower (p < 0.05), consistent with reduced serum E2 and reduced cardiac pNOS3 (Ser1119 ) in these mice. Treatment of ileal lymphocytes with E2 reduced gut inflammation in WT but not IL-10 KO mice. In conclusion, our data suggest that diminished estrogen and defective bone mineralization increased FGF23 which contributed to cardiac fibrosis in the IL-10 KO mouse.

Pulse Supplementation Improves Gut Health and Lowers Total Cholesterol in Postmenopausal Women

Objectives

Menopause is associated with many physiological changes as well as increased risk of obesity, cardiovascular disease, type 2 diabetes, and gut-related diseases (i.e. irritable bowel syndrome, inflammatory bowel disease, colon cancer). Data regarding the use of pulse crops in alleviating health risks associated with menopause are limited. This study investigated the effects of pulse supplementation on markers of gut health and metabolic outcomes in postmenopausal women.

Methods

Thirty-five postmenopausal (≥1 year without menstruation) women, ages 45–70 years old, who were not on hormone replacement therapy, probiotics, antibiotics, multiple supplements, or medications that affect lipids or glucose, were recruited for this clinical study. Study participants were asked to consume 100 g of pulses (alternate between chickpeas, kidney beans, pinto beans, black-eyed peas, and lentils) daily for 12 wks, and to maintain their normal diet and lifestyle. Anthropometric measures including body composition by dual-energy X-ray absorptiometry, plasma lipids and glucose, fecal short chain fatty acids (SCFAs), and stool characteristics (Bristol Stool Chart and the Cleveland Clinic Constipation Scoring System) were assessed before and at the end of 12-wk supplementation. P < 0.05 was considered statistically significant.

Results

There were no differences in anthropometric measures and plasma glucose at the end of the 12-wk supplementation compared to baseline. However, a reduction in plasma total cholesterol (p = 0.039) and LDL-C (p = 0.026), but an increase in both VLDL-C (p = 0.031) and triglycerides (p = 0.033) were observed with pulse supplementation. Constipation score significantly improved (p = 0.003) but no change in stool quality were observed with pulse supplementation. Fecal acetic acid (p< 0.001), n-butyric (p = 0.038), n-caproic (p = 0.004) and total SCFAs (p = 0.001) were also significantly increased with pulse supplementation.

Conclusions

Our findings demonstrate that 12 wks of pulse supplementation improved markers of gut health and lowers total- and LDL-cholesterol in postmenopausal women. This population who are at an increased risk for cardiovascular and gut-related diseases can benefit from regularly consuming pulses.

Funding Sources

USDA Award Pulse Crop Health Initiative (#58-3060-0-048) and the Jim and Lynn Williams Professorship

Wheatgerm Supplementation Reduces Gut Inflammation and Epithelial Barrier Dysfunction in IL-10 KO Mice Fed Atherogenic Diet

Objectives

Wheat germ (WG) contains many bioactive compounds with the potential to maintain an anti-inflammatory gut environment. This study investigated the effects of WG supplementation on gut inflammation and integrity in high-fat fed interleukin (IL)-10 KO mice.

Methods

Eight-wk-old female B6.129P2-Il10tm1Cgn/J (IL-10KO) and C57BL/6 (WT) mice (n = 10/group) were randomly assigned to diets: WT fed a control diet (WTCO; AIN93-M) and IL-10 KO mice fed control (KOCO), high-fat with high-cholesterol (HFHC; 45% fat kcal, 1% cholesterol), or HFHC + 10% WG (HFWG) for 3 m. Disease activity indices (fecal blood, ruffled fur, stool softness, and rectal prolapse) were monitored twice a week. Fecal indole and short chain fatty acids (SCFAs) concentration were assessed at the beginning and end of study. Proinflammatory cytokines were assessed in the serum and ileum. Ileal and colonic protein expression of transcription factors (STAT3, p-STAT3, PPARg, FoxP3, and AhR), tight junction proteins (ZO-1, occludin), and tryptophan catabolizing enzyme (IDO-1) were assessed by immunoblotting. Relative ileal and colonic gene expression of IL-22 and antimicrobial peptides (Reg3b and Reg3g) were assessed using qRT-PCR. P &lt; 0.05 was considered statistically significant.

Results

WG increased (P = 0.003) colon length compared to the HFHC group. Weight loss (12.2% in HFHC vs WTCO) was not prevented by WG, but disease activity indices were significantly reduced in the WG vs HFHC group. WG also increased fecal indole, total SCFAs and acetate accompanied by an increase in colonic protein expression of PPARg (P &lt; 0.0001) and FoxP3 (P = 0.001). Ileal STAT3 phosphorylation was reduced (P = 0.0076) due to WG supplementation. An increased colon and ileal protein expression of IDO-1 in the HFHS group was reduced by WG, while also increasing the expression of AhR, ZO-1, and occludin. The relative gene expression of the antimicrobial peptides (Reg3b and Reg3g) was increased (P &lt; 0.05) while serum and ileal tissue concentration of the proinflammatory cytokine, IL-17 was reduced (P = 0.0165 and p = 0.0248 respectively) by WG.

Conclusions

WG modulated changes that are associated with HF-feeding in IL-10 KO mice, and might be a promising regimen for ameliorating the effects of gut inflammation.

Funding Sources

Oklahoma Agriculture Experiment Station, Jim and Lynn Williams Professorship, and Barbara K. Pass Grant.

POS0098 LINC01871, IMPLICATED IN SJÖGREN’S DISEASE PATHOGENESIS, IS REGULATED BY INTERFERON-G AND CALCINEURIN SIGNALING

Background

Sjögren’s disease (SjD) is an autoimmune disease characterized by exocrine gland dysfunction. Long non-coding RNAs (lncRNAs) are a functionally diverse class of non-protein coding RNAs that are longer than 200 nucleotides. Our previous study using whole blood RNA-seq found that lncRNA, LINC01871, is overexpressed in SjD relative to controls [1]. CRISPR-Cas9 targeting in HSB2 T cells yielded a LINC01871-/- clone with altered expression of many genes implicated in immune regulation [1].

Objectives

The goal of this study was to analyze the gene expression perturbations resulting from the loss of LINC01871 and to characterize the regulation of LINC01871 in both the LINC01871-/- clone and primary human T cells in response to immune stimuli.

Methods

Flow cytometry and LegendPlex bead assays were used to compare surface and secreted protein expression changes, respectively, in LINC01871-/- cells and the parental HSB2 cells. Parental HSB2 T cells, LINC01871-/- cells, Kasumi-3 myeloid cells, and primary human T cells were stimulated in vitro and changes in gene expression were measured over time using qRT-PCR. Responses to interferons (IFN) were assessed using universal type I IFN (IFNα) or IFNγ. TCR signaling responses were assessed using PMA/Ionomycin (PMA/I) or anti-CD3/CD28 stimulations in the presence or absence of the calcineurin inhibitor, FK506.

Results

Previous RNA-seq analysis found 1166 differentially expressed (DE) transcripts (log2FC ≥1 or ≤-1; padj ≤0.05) in LINC01871-/- cells compared to parental HSB2 cells, including many prominent immune regulatory genes. Changes in the basal expression of 7 proteins in LINC01871-/- cells were confirmed using flow cytometry (significantly decreased: CD8a (p=0.0004), CD30 (p=0.0008), CXCR3 (p=0.037), T-Bet (p=0.0002), and Aiolos (p=0.02); significantly increased: CD226 (p=0.0059) and CD44 (p=0.024)). Analysis of LINC01871-/- cells revealed a growth inhibition in LINC01871-/- cells (p=0.0014 at 72h), in which multiple secreted growth and adhesion factors were significantly reduced: GM-CSF (p=2.0e-06), M-CSF (p=2.7e-09), IGBPF4 (p=1.2e-07), s-ICAM1 (p=0.015), MMP9 (p=3.0e-14), and MMP2 (p=6e-08). In contrast, the IL-6 cytokine family member, LIF, was significantly increased in LINC01871-/- cells (p=1.2e-07). Because HSB2 cells were not responsive to all IFNs, IFN-mediated regulation of LINC01871 expression was examined in the Kasumi-3 myeloid cell line. While LINC01871 expression was not modulated by type I IFN stimulation, it was robustly responsive to IFNγ treatment. Since LINC01871 was expressed in T cells and implicated in T cell pathways, responses to TCR signaling pathways were characterized in HSB2 cells or purified primary human T cells treated with PMA/I. In both cell types, LINC01871 exhibited a prolonged decrease in expression that was abrogated by concurrent treatment with FK506, indicating that LINC01871 is regulated by calcineurin signaling. Treatment of primary human T cells with anti-CD3/CD28 to mimic true TCR engagement resulted in a modest decrease of LINC01871 expression at early time points, followed by an increase in expression with longer stimulation (2d).

Conclusion

Our findings suggest that LINC01871 is a potential mediator of the dysregulated T cell inflammatory response pathways implicated in SjD pathogenesis. LINC01871 influences the expression of many important immune cell genes and growth factors, is inducible by IFNγ, and is regulated directly by calcineurin signaling and TCR ligand engagement. Although LINC01871 functions are still unknown, observed LINC01871 overexpression in whole blood of SjD cases and after prolonged TCR stimulation in primary human T cells suggests that it could be a biomarker of SjD.

References

[1]Joachims, et al. Annals of the Rheumatic Diseases 2020;79:90.

Disclosure of Interests

Michelle L Joachims: None declared, Bhuwan Khatri: None declared, Chuang Li: None declared, Kandice L Tessneer: None declared, John Ice: None declared, Anna M Stolarczyk: None declared, Nicolas Means: None declared, Kiely Grundahl: None declared, Stuart Glenn: None declared, Jennifer Kelly: None declared, David Lewis: None declared, Lida Radfar: None declared, Donald Stone: None declared, Joel Guthridge: None declared, Judith A. James: None declared, R Hal Scofield: None declared, Graham B Wiley: None declared, Jonathan Wren: None declared, Patrick M Gaffney: None declared, Courtney Montgomery: None declared, Kathy Sivils Employee of: Current employee of Janssen., Astrid Rasmussen: None declared, A Darise Farris: None declared, Indra Adrianto: None declared, Christopher Lessard: None declared

Wheat Germ Supplementation Improves Glucose Homeostasis Markers of Overweight Adults Independent of Gut Microbial Modulation

Objectives

This study investigated the effects of wheat germ (WG) supplementation on inflammation, metabolic, and gut health markers in overweight adults.

Methods

Forty overweight (BMI = 25.0–30 kg/m2) adults between 18–45 y old were recruited to this single-blinded randomized placebo-controlled study. Qualified participants were asked to maintain their normal diet and physical activity and consume energy balls containing 30 g of either WG or cornmeal (control) daily for 4 wks. Anthropometric and metabolic parameters, as well as dietary (3-d food record), medical history, physical activity (Yale Physical Activity Survey), stool measures (Bristol Stool Chart and the Cleveland Clinic Constipation Scoring System), gut integrity markers, and fecal bacterial population were assessed at baseline and at the end of the supplementation period.

Results

Thirty-nine participants completed the 4-week study (n = 20 and 19 for the WG and control group, respectively). There were no differences in the lipid profile, but glycated hemoglobin (P = 0.04), insulin (P = 0.03), and homeostatic model assessment of insulin resistance (HOMA-IR; P = 0.04) were significantly decreased in the WG but not the control group. Similarly, the adipokine resistin was also significantly reduced (P = 0.03) by WG but not the control. There were no changes in stool characteristics between the two groups before and after supplementation. Similarly, there were no changes in gut bacterial population due to WG supplementation but the phyla Bacteroidetes (P = 0.03) and Proteobacteria (P = 0.048) and the genus Bacteroides (P = 0.03) were significantly decreased in the control group. No significant changes were observed in plasma inflammatory markers, fecal short-chain fatty acid (SCFA) concentrations, and markers of gut integrity in both groups.

Conclusions

Four weeks of WG supplementation improved markers of glucose homeostasis, which can partly be attributed to the reduction of the pro-inflammatory adipokine resistin and not due to changes within the gut (i.e., bacterial population, gut integrity markers, and SCFA production). Our findings indicate that WG may be a safe, effective, and economical approach to improve glucose homeostasis.

Funding Sources

USDA Award #2019–67,018-29,260 and the Jim and Lynn Williams Professorship.

Interleukin (IL)-10 Is Important in the Maintenance of Trabecular and Cortical Bone and Protects Against Western Diet-Induced Disruption in Bone Remodeling in Mice

Objectives

The purpose of this study was to investigate if consumption of a western diet (WD) exacerbates the effects of loss of function of IL-10, an anti-inflammatory cytokine, on biomarkers of bone metabolism and microarchitecture.

Methods

Six-week-old male B6.129P2-Il10tm1Cgn/J (IL-10 KO) and C57BL/6 mice (WT) were randomized to treatment in a 2 × 2 factorial with diet (AIN-93 control diet CD vs WD) and strain (IL-10 KO vs WT) as factors. Due to potential influence of high fat on intestinal Ca absorption, a WD diet with added Ca (1.2 g/kg) was used. After 12 wks, whole body dual-energy x-ray absorptiometry scans were performed to assess bone density and body composition, and micro-computed x-ray tomography was used to evaluate trabecular and cortical bone microarchitecture in the femur and lumbar vertebra. Serum biomarkers of bone formation, procollagen 1 intact N-terminal propeptide (P1NP), and resorption, c-terminal telopeptide of type I collagen (CTX-1) were assessed.

Results

Body weight, but not % body fat, was lower (P &lt; 0.05) in IL-10 KO mice relative to WT controls. 12 weeks of WD increased (P &lt; 0.05) body weight and % fat, but the response was not as great in the IL-10 KO mice. Bone mineral density and content were lower in IL-10 KO mice compared to WT, and the WD had no effect on these parameters. The IL-10 KO mice exhibited a decrease in trabecular bone volume, thickness, and number, and an increase in trabecular separation and structure model index compared to WT mice within the femur and vertebrae. The WD had no effect on these trabecular bone parameters. Cortical bone thickness and area were reduced (P &lt; 0.05) and porosity increased in both the femur and vertebra of IL-10 KO mice relative to their WT counterparts. This strain effect was not altered by the WD. IL-10 KO mice exhibited a significantly lower serum PINP and higher CTX-1 compared to the WT mice. Despite the lack of structural changes in bone after 12 wks, the WD increased (P &lt; 0.05) CTX-1 and tended to suppress P1NP (P = 0.051) in the IL-10 KO mice compared to WT.

Conclusions

We conclude that IL-10 plays an important role in bone metabolism and maintaining structural properties and in the absence of IL-10, WD negatively affects both osteoclast and osteoblast activity. Further studies are warranted to determine if structural changes occur with longer exposure to WD.

Funding Sources

Oklahoma Agricultural Experiment Station.

Understanding How Sex Influences the Impact of IL-10 on Bone Microarchitecture and Bone Metabolism Over Time

Objectives

Dietary interventions with pre- and probiotics favorably affect the gut-bone axis, mediated in part by the anti-inflammatory cytokine, interleukin (IL)-10. This study sought to understand how IL-10’s impact on bone metabolism and microarchitecture differs with sex and time.

Methods

Six-week-old B6.129P2-Il10tm1Cgn/J (KO) and C57BL/6 (WT) mice were assigned in a 2 × 2 × 2 factorial design with strain (WT & KO), sex, and time (3 & 6 m) as factors. Mice were fed AIN-93G diet for 3 m followed by AIN-93 M for the study duration. Dual-energy x-ray absorptiometry was used to assess bone mineral content (BMC) and density (BMD). Micro-computed tomography was used to assess femur and lumbar vertebrae trabecular and cortical bone. Serum procollagen 1 intact N-terminal propeptide (P1NP) and C-terminal telopeptide of type I collagen (CTX-1), bone formation and resorption markers respectively, were assessed by ELISA. Data were analyzed using ANOVA; p &lt; 0.05 was considered significant.

Results

Reductions in BMC and BMD (P &lt; 0.05) in KO vs WT and at 3 vs 6 m were observed; a sex effect was found with reductions in BMC in KO females compared to KO males. Femoral trabecular bone volume (BV/TV) was lower (P &lt; 0.05) in KO vs WT, females vs males, and at 6 vs 3 m. Trabecular thickness (TbTh) decreased (P &lt; 0.05) in KO vs WT and increased from 3 to 6 m, while decreases in trabecular number (TbN) were greater (P &lt; 0.05) in KO mice, females, and at 6 m compared to counterparts. Cortical area and thickness were decreased (P &lt; 0.05) in KO vs WT and in females vs males, which was greater at 6 m, while cortical bone porosity was higher in KO vs WT and increased at 6 mo. Vertebral trabecular BV/TV was lower (P &lt; 0.05) in KO vs WT at 3 and 6 m, with KO females showing reduced BV/TV (P &lt; 0.05) from 3 to 6 m. Reduced TbTh and TbN were observed in KO vs WT, and females had increased (P &lt; 0.05) TbTh and trabecular separation and reduced TbN. P1NP showed a time effect (P &lt; 0.05) with reductions in WT females and males at 6 m compared to 3 m KO females (P &lt; 0.05). CTX-1 shows a sex effect (P &lt; 0.05) and a trending strain effect (P = 0.059), with elevated serum CTX-1 in 3 m KO males compared to WT and KO females at 6 m (P &lt; 0.05).

Conclusions

While IL-10 plays an important role in maintaining both trabecular and cortical bone, it may have a more protective effect on the cortical bone of female mice over time.

Funding Sources

Oklahoma Agricultural Experiment Station.

Loss of Interleukin (IL)-10 Is Associated With Increased Vascular Inflammation and Sex-Differences in Metabolic Outcomes of Normal Diet-Fed Mice

Objectives

The anti-inflammatory cytokine, IL-10, plays an important role in reducing the risk of many inflammatory diseases. This study investigated the time and sex effects of IL-10 gene deletion on metabolic risk factors that contribute to the development of cardiovascular disease.

Methods

Six-wk-old male and female B6.129P2-Il10tm1Cgn/J (IL-10−/−) and C57BL/6 (WT) mice (n = 12–16/group) were randomly assigned to 12- or 24-wk time points and were fed growth (AIN-93G) diet up to 3 m of age and then maintenance diet (AIN-93M) for the remainder of the study. Monthly fasting glucose was assessed as well as intraperitoneal glucose tolerance test (ipGTT), body composition, and serum metabolic parameters at each study end point. Cardiac and vascular adhesion molecules, macrophage marker F4/80, and sterol metabolism genes were assessed using qPCR. Data were analyzed using t-test and 2-way ANOVA with strain and gender as factors, and α = 0.05.

Results

IL-10 deletion resulted in weight loss (p &lt; 0.05) coinciding with reduced fat mass and % fat (P &lt; 0.05) in both sexes of IL-10−/−. Loss of IL-10 had no effect on fasting glucose at any time point in either sex; however, a delayed response to glucose challenge and increased AUC with the ipGTT (P &lt; 0.05) occurred in male IL-10−/− vs WT mice. No strain effect was observed on serum lipids at 12 wks, but cholesterol and high-density lipoprotein (HDL)-C were reduced (P &lt; 0.05) in IL-10−/− vs WT mice at 24 wks. Only male IL-10−/− mice exhibited elevated (P &lt; 0.05) non-HDL cholesterol and tended (P = 0.072) to have elevated triglycerides vs WT mice at 24 wks. In conjunction with serum lipid changes, male IL-10−/− mice increased (P &lt; 0.05) hepatic transcription of β-hydroxy β-methylglutaryl-CoA (HMG-CoA), whereas HMGCoA transcript tended to be repressed (≥ −53.5%; P = 0.08) in female IL-10−/− vs WT mice. At 12 and 24 wks, IL-10−/− exhibited increased (P &lt; 0.05) circulating c-reactive protein and aortic and cardiac gene expression of VCAM-1, ICAM-1, and iNOS. The only increase in the F4/80 macrophage marker occurred in male IL-10−/− mice vs WT at 24 wks.

Conclusions

Loss of IL-10 was associated with different metabolic responses in male and female mice and could be detrimental to cholesterol-mediated metabolic processes in female mice on a control diet.

Funding Sources

Oklahoma Agriculture Experiment Station and the Jim and Lynn Williams Professorship.